The present invention relates generally to video tracking systems, and more particularly, to an improved video tracking system that employs clutter detection wherein target information and scene objects are used to automatically decrease the system bandwidth to reduce perturbations from clutter during interference.
Conventional video trackers detect clutter on a very local level and enter into a "coast" state by setting the system bandwidth (gain) to zero for a period of time during expected interference, using a previously computed target rate estimate to predict the target position during the time period. Target maneuvers during a coast event may cause the target to be lost irreparably.
Kalman filters and extended Kalman filtering are used in some video tracking systems to automatically change the system bandwidth (gain) according to changes in target position measurements. Typical Kalman filters vary the bandwidth depending on how well the target position measurements match dynamic model predictions. When the match is good, the system bandwidth is reduced, thus, measurements are weighted less. When the match is poor, the system bandwidth is increased and the model parameters are updated for the new measurements. Unless the Kalman filter is augmented for predicted interference, the filter updates the model parameters during the interference period, exactly the opposite of what is desired. Thus, Kalman filters actually increase the system bandwidth during perturbations. Kalman filtering cannot estimate the length of the interference, and must rely on target position measurements alone to drive the system bandwidth back to normal.
Accordingly, it is an objective of the present invention to provide for a video tracking system that overcomes the limitations of conventional tracking systems. It is also an objective to provide for a video tracking system that employs clutter detection wherein target information and scene objects are used to automatically decrease the system bandwidth to reduce perturbations from clutter during interference.